Girder units



March 14, 1961 E. M. HUNNEBECK GIRDER UNITS 3 Sheets-Sheet 1 Filed D60. 2, 1958 FIG. I

FIG. 5

INVENTOR EMIL MAURITZ HUNNEBECK ATTORNEYS .March 14, 1961 E. M. HUNNEBECK GIRDER UNITS 3 Sheets-Sheet 2 Filed Dec. 2, 1958 INVENTOR EMIL MAURITZ HENNEBECK ATTORNEYS March 14, 1961 E. M. HUNNEBECK GIRDER UNITS 3 Sheets-Sheet 3 Filed Dec. 2. 1958 INVENITOR EMIL MAURITZ HUNNEBECK ATTORNEYS United States Patent O i GIRDER UNITS Emil Mauritz Hunueheck, Achenbackstr. 5, Dusseldorf, Germany Filed Dec. 2, 1958, Ser. No. 777,634 Claims priority, application Germany Sept. 23, 1952 14 Claims. (Cl. 189-37) This invention relates to temporary extensible girder units for the temporary support of loads, such as concrete floors, and the like, and has for its object the provision of certain improvements in girders and extensible girder umts.

The girder units are light in Weight and formed of girders that are preferably cambered and have equal load carrying capacity. The girder units may be assembled and disassembled with facility and can be removed from a concrete floor without vibration or blows or jerks that would injure the concrete.

The extensible girder unit of the invention comprises at least one outer girder and at least one inner girder in telescopic slidable connection inside the outer girder. The outer girder not only has an open center, but it is open at both ends for the insertion of an inner girder from either'end, whereby a girder unit comprising two or more of each girders may be connected together telescopically to form long units.

The extensible girder unit of the invention is preferably formed of cambered girders each of which has a bearing flange at one end for supporting the girder unit. Each inner girder has a single projecting flange on at least one end, and each outer girder has a flange on at least one end consisting of two spaced flanges attached at the sides so as to provide a space for the insertion therein of the inner girder and the single flange of the inner girder. The flange of the inner girder is flush on top with the top of the inner girder. The flanges of the outer girder are preferably attached along the sides to the outer girder and are also flush on top with the upper surface of the outer girder. This construction and arrangement of flanges makes it possible for the inner girder to beinsorted into the open end of the outer girder sothat the tops of the flanges of the outer girder are substantially flush with the top of the inner girder. This enables the concrete form which is applied over and supported by the girder unit to bear evenly on both girders. Another important feature of the flange construction and arrangement is that the single flange can fit inside the double flanges at a common support area thus enabling a series of the girder units to be arranged in a straight line, whereas otherwise it would be necessary to displace them in alternate arrangement, one alongside of another.

'and in which the inner girder is laterally guided, both girders being suitably arched or cambered to an extent depending on the permissible stress to be imposed on them. The clamping means are constructed to hold the inner girder to the'outer girder in'any desired position 2,974,762 Patented Mar. 14, 1961 and to adjust the distance between the girders, and also to release them so that they may be buckled to remove them from the supported concrete. The invention includes also a particularly advantageous construction of the girders as well as certain relationships between their dimensions which increase the usefulness of the girder unit.

The invention is illustrated diagrammatically in the accompanying drawings which show various forms of construction and examples of uses of the girder units.- In the drawings:

Fig. 1 is a plan view of a girder unit consisting of one outer and two inner girders;

Figs. 2-4 are side elevations showing the girder unit of Fig. 1 in diflerent positions;

Fig. 5 is a side elevation of a girder unit consisting of one outer girder and one inner girder, in the lowered condition;

Fig. 6 is an elevation showing the inner girder completely inserted into the outer girder for transport;

Fig. 7 shows a girder unit consisting of three outer and three inner girders;

Fig. 8 illustrates an arched girder unit in side elevation;

Fig. 9 is an enlarged view showing an area of connection of the girder unit of Fig. 8;

Fig. 10 is a fragmentary enlarged view of the outer and inner girders in connected position;

Fig. 11 is a cross-section at 11-11 in Fig. 10;

Fig. 12 is a plan of a rigid bridge member used in Figs. 10 and 11;

Fig. 13 is a perspective of another form of girder unit;

Fig. 14 is an enlarged sectional view at 1414 of Fig. 13, and

Fig. 15 is a plan view of another arrangement of girder units.

As illustrated in Figs. 1 to 12, the girder unit comprises one or more outer girders 1 and one or more inner girders 2. The outer girder has an open center and is open at each end for the insertion therein and completely therethrough of the inner girder (see Fig. 11).

The outer girder has an upper chord 3 which is preferably cambered having a cross-section in the general form of a U or channel with a flat top 4, depending sides 5 and 6 and lateral flanges 7 and 8. One end has an extending flangefsupport formed of two side parts 12 and 13 each fastened to one side of the chord 3 and flush with the top of the chord. These flange parts are preferably slightly wedge-shaped, being tapered outwardly (Fig. 13) to facilitate their removal from the concrete. As shown in Figs. 1 to 9, the lower chord 14 includes two rods 15 and 16 held in spaced relation by cross bars 18 and 19. As shown in Fig. 5, the girders can be buckled with the inner girder dropping through the open bottom of chord 14. This facilitates removal of the gridders from the concrete floor. Instead of using the two rods which provide an open bottom for the girder I may use a chord formed of a single bar which closes the bottom as in Fig. 13. At positions approximately twice the depth of the girder the rods 15 and 16 turn upwardly and are connected at their ends to the top chord 3.

Two zigzag or wave-like'trusses 20 and 21 are connected at the tops of the crests C to the flanges 7 and 8 and at the bottoms of the crests C to the rods 15 and 16, respectively. At the position where the rods 15 and 16 turn upwardly, the cross bars 18 and 19 form rigid bridges which are threaded to receive the clamping screws 22 and 23. These bridges are located from the ends a distance approximately double the height of the outer girder. These screws bear on plates 24 and 25 which are slidable over the guide rods 26, 27 and 28, 29 extending from the rods 15 and 16 to the flanges 7 and 8. These ,guide rods maybe separate or integral with the lattice trusses as illustrated.

Fig. 11 shows the outer girder to be rectangular in cross-section; however, it may. have-other shapes as with inclined sides giving a trapezoidalshape as in Figs. 13 .and 14.

The inner girder illustrated in Figs. 1 to. 12 has an upper'chord 30 formed or" two channel bars 51 .and 32 connected to a fiat web 33 and a lower chord seformed of two channel bars 35 and 36 which are also connected -to the web 33. This girder has sloping ends .37 and 38 -to facilitate removal from the supported floor including projecting end portions 39 and ii. of which form depending lugs to prevent the inner girder from slipping out oi 'the' position when the girder unit is positioned for transport as shown in Fig. .6.

a One end of the girder has a projecting support flange 41 which is the width of the upper .chord and flush wi the top thereof and also wedge-shaped, beingtapered towards its free end. The other end of the girder has a bar 42 connected to the end 33 by bolt 43. This bolt is .in a slot of bar 42 which permits the bar to be raised to bear against the under surface of the upper chord 3 as shown in Fig. 10. The lower girder may be formed as shown in Figs. 13 and 14.

As shown in Figs. 1 to 12, the outer and inner girders may form girder units consisting of several girders in combinations of one or more outer girders and one or -more inner girders.

The inner girder 2 can be pushed partly into the outer girder 1 as shown in Figs. 1 to 5, or completely as shown in Fig. 6 for transport and storage. The length can be adjusted as desired by inserting the inner girder into the outer girder to a greater or lesser distanceand by using similar girders the girder unit can be extended as desired. In order that the girder unit, which is supported only at the flanged ends, may be loaded, the inter-engaging inner and outer girders must be firmly fixed together by the H screws 22 and 2-3. The compressive forces of the screws vary according to the extent to which the inner girder is inserted into the outer girder. The compressive forces are relatively great when the girder elements are fixed together with minimum overlap and when two outer girders .1 are connected by an inner girder 2 which is inserted only a minimum distance into them. It has been deter- .mined by calculation and experiment that the forces which occur in all the positions in question do not result in any excessive stress, if the bridges 18 and 19 are at the a stated distance from the ends of the outer girder which is about twice the height of the outer girder. The inner girder has, of course, to take the same compressive stresses at the places where it is clamped to the outer girder.

The inner girder, in accordance also with the invention, is preferably shorter than the outer girder by the smallest distance by which it may be inserted into the outer girder, that is to say, by double the height of the .outer girder. The effect of this is that any desired width .of span can be bridged with only a singlekind of inner and outer girders. In an outer girder into which an inner girder has been inserted only to the minimum distance from one end, a second inner girder can be inserted to its full length from the other end, so that by withdrawing the latter girder the length can be directly increased. In a similar manner the length of the girder unit can be increased by using other girders as shown in Fig. 7.

If inner girders 2 and an outer girder 1 are alternately connected, as shown in Fig. 2, the maximum camber necessary i.e. the distance a, in Fig. 2 is positively deterrni ned. The camber can be reduced when the stress is less, for example, to the amount b, shown in Fig. 3 by withdrawing the screw 22. If this is done, however, the inner-end of the girder 2 no longer bears on the girder 1.

.Figs. 4 and 5 show the girder unit lowered, the screw l22ihaving been completely unscrewed. The girder unit 4 has been lowered by the amount 0 below the horizontal i.e. below the plane of the under side of the ceiling (which had been supported-not shown) which can take place quite gradually and without shock. The parts of the girder unit when in this released condition still support themselves so that it is possible to'remove them without danger. For this purpose, one of the inner girders 2 is pushed inwardly until it loses its support after which it can be easily removed. The inner girder can be easily pushed inwards by inserting 'a short lever between the supporting wall and the end of the girder.

The outer and inner girders can be assembled in any suitable succession for bridging spans of diiferent widths,

tor the spans of adjacent pairs of girder units, the righthand pair of girders having the maximum span.

In the case of units for arcs of greater curvature, as shown in Figs. 89, the adjacent girders enclose between them a larger acute angle, so that a triangular space is formed, as shown in Fig. 9, between the upper chord of the inner girder 2 and the outer girder 1. In this space is inserted a key or wedge 45, whereby the end of the outer girder is supported on the inner girder and the connection is completed. Instead of a single doublekey, two separate keys or wedges may be used. For making such a unit in which the girders are inclined at an angle to one another, for example, for a sloping roof, it is necessary that the heights of the inner girders should bear a definite relation to one another in order to be able to form a polygonal outline. This relationship is also important, on the one hand, in order to enable the unitto be struck by lowering the girder, and, on the other'hand, to give the girders the necessary supporting power for taking the compressive and traverse forces to which they are subject. Experiments have shown that the ratio of the height of the inner girder to the height of the outer girder should not be less than 9: 13. 7

When striking the unit shown in Fig. 8, the screw 23 at the upper end of the highest outer girder is released,

whereby the entire girder is freed from stress. The uppermost inner girder is then pushed inwards, after which the entire arch can be lowered about its left-hand support as a pivot.

The inner girders shown in Fig. 8 have only half the length of the outer girders. They can, however, also be used for straight beams.

The girder units of the invention, owing to their rug- .ged construction, are suitable for rough work, but are nevertheless comparatively light. a

The girder unit illustrated in Figs. 13 and 14 comprise an outer girder 50 and an inner girder 51. The outer girder has atop chord S2 in the form of a channel having the lower edges 53 and 54 turned inwardly. Two projecting and supporting end flanges 55 and 56 are attached to the sides of the chord at one end. These flanges are even with the top of the chord 52 and are sufiiciently spaced apart to permit the insertion of the inner girder and also the flange to the inner girder. The wedge shape The inner girder 51 has an upper chord 72 in the form ofa triangle the flat top of which bears on the flat top of chord 52. The triangle has depending legs 73 and 74 connected to a web 75. The lower chord 76 consists of two angle bars 77 and 78 connected to the web. The ends of the inner girder have plates 80 and 81 which close the space in the upper chord. This form of beam is very advantageous because the top chord can be completely sealed to prevent the entrance of water or fresh concrete and the lower chord will not hold water and any concrete that may fall on it can be removed easily. Moreover, this girder has a high resistance to twisting and bending and is relatively free of projecting edges. Also, it has a flat top and bottom. One end of the inner girder has a projecting flange 82 which is about the width of the top chord and which can slide inside the top chord 52 and between the flanges 55 and 56. Flange 82 is also tapered similarly to flanges 55 and 56 in the horizontalplane. There is suflicient clearance between the top of the lower chord 57 and the bottom of the chord 76 sothat when the screws 62 and 63 are withdrawn the girders can be buckled to remove them from the floor they support.

Fig. 15 illustrates one of the important features of the girders of the invention. The girder unit U consisting of an inner girder and an outer girder are in spanning position between the walls W and W. The girder unit U' consisting of an inner girder and an outer girder are in spanning position between the walls W and W. It

be noted that both units extend in a straight line by reason of the fact that the flange 82 of the inner girder fits between the flanges 55 and 56 of the outer girder. This is very important in supporting heavy floors where the girder units must be placed close together and extended across several walls.

This application is a continuation-in-part of my application Serial No. 373,836, filed August 12, 1953, now abandoned.

I claim:

1. In a girder unit having at least one outer girder open in the center and an inner girder telescopically slidable in the open center of the outer girder, and clamping means securing the two girders together at any desired extended position of the inner girder, the improvement which comprises a support flange extending from one end of the inner girder which is the approximate width of the inner girder, and a supporting flange secured to one end of the outer girder having two extending parts with a space therebetween the approximate width of the support flange of the inner girder, the two extending parts being flush with the upper surface of its girder, whereby any desired number of said girders may be arranged in a straight line with the flange of an inner girder inserted between the extending parts of an outer girder.

2. A girder unit comprising at least one outer girder open at the center and one end, an inner girder telescopically slidable in the outer girder through the open end, a projecting flange at one end of the inner girder which is about the width of the inner girder, a flange projecting from and secured to one end of the outer girder consisting of two spaced extending parts providing a space therebetween in which the flange of the inner girder can be inserted, the flanges of the inner girder and the outer girder being flush with the tops of their respective girders, the space inside the outer girder being so much greater in vertical depth than the inner girder that the inner girder can move up and down therein, an means near one end of the outer girder for clamping the inner girder thereto.

3. An assembly of girder units which comprises at least two outer girders each of which is open at the center and at each end, an inner girder in telescopic slidable connection inside each of said two outer girders connecting the outer girders together, and another inner girder telescopically slidable through an open end of one of the outer girders, each outer girder being appreciably greater in vertical depth than the inner girder and having an open bottom whereby the inner girder can be moved up and down and angularly inside the outer girder, and means near the end of each outer girder for clamping the inner girder thereto, said clamping means being located from the end of the outer girder about twice the depth of the outer girder. I

4. A temporary support for concrete construction comprising an innergirder, an outer girder in which the inner girder is slidable and having an upper chord of U- shaped cross-section with the free ends of the legs thereof flanged outwardly along substantially the entire length thereof, upright lattice trusses fixed to said flanges, along the length thereof, said trusses having upright end stays, rigid bridges connecting said end stays, and a screw threaded through each of said bridges including means for hearing against 'said inner girder to hold it in adjustable supporting engagement with the outer girder.

5. A temporary support for concrete construction comprising an inner girder, an outer girder in which said inner girder is slidable and having an upper chord of U- shaped cross-section with its free ends flanged and upright lattice trusses fixed to said flanges, each end of said trusses having an upright end stay at a distance from the end of the truss approximately equal to double the height of the outer girder, rigid bridges connecting said end stays, plates slidable on said end stays for hearing against and supporting said inner girder element, and screws threaded through said bridges for clamping the inner girder to the outer girder, said inner and outer girders having approximately the same carrying power.

6. A temporary support for concrete construction comprising a girder unit having a plurality of outer girders, an inner girder slidable longitudinally within each of the outer girders, said girders having approximately the same carrying power, supporting means for the inner girder at a distance from the ends of the outer girder approximately equal to double the height of the outer girder, means for adjusting the height of said girder unit, and keys disposed in the space between the ends of the outer girder and the upper side of the inner girder for supporting the adjacent ends of the outer girders from the inner girder.

7. A temporary support for concrete construction comprising an outer double girder having parallel lattice trusses with upright end stays, an inner girder longitudinally slidable in said outer girder, bridges rigidly connecting the end stays of said lattice trusses, adjustable means in said bridges for supporting said inner girder,

said inner girder being shorter than said outer element by approximately double the height of the outer girder, and adjustable means on the end of the inner girder for supporting the outer girder.

8. A temporary support for concrete construction comprising an outer girder having upright lattice trusses with vertical end stays, an inner girder comprising a web and chord longitudinally slidable in said outer girder, bridge means rigidly connecting said end stays, plates retained on and displaceable along said end stays, and screws threaded through said bridges and bearing on said plates for supporting said inner girder.

9. A temporary support for concrete construction comprising an outer girder in the form of a box-like framework having spaced apart upright sides and being open on the underside, an inner girder slidable longitudinally within the outer girder, said inner girder having a width permitting it to pass into the opening in the underside of the outer girder, a rigid bridge connecting said upright sides of said framework, and an adjustable support for 7 zcludes ;at .said ends, near the uppermost surface, means {or suspension from a supporting structure;

11;A temporary support forconcrete construction com- ,prising' an outer girder in the for'mof a box-like frame- -.work having spaced sides, said outer girder being opened at each end to receive an inner girder, a rigid bridge connecting the sides of the outer girder near each of the. ends thereof, at least one inner girder extending throughan open end of the outer girder, said inner girder being 'slidable within said outer girder and adjustable relative to said outer girder to positions where the top sides of the chords of the inner and outer girders form an angle less than a straight angle, and means carried ;by .-said rigid bridge for holding the inner girder in an adjusted position relative to said outer girder, the bottom ,of said outer girder being open inwardly from each of said rigid bridgesso that when the inner and outer girders are adjusted to said angle the inner end of the inner girder mayextend through the bottom of the outer .girder. 12. A temporary support as claimed in claim 11 in which the outer girder has vertical stays extending at each side from the rigid members to the chord thereof, carrier plates for the inner girder slidably mounted on I said vertical stays, and screw means carried by the rigid bridge and engageable with the carrier plates for clamping the inner girder in its relatively adjusted position to the outer girder. 13. A temporary support for vconcrete construction adapted to 'be removed by buckling inwardly comprising at least one outer girder and at least one inner girder, the outer girder having spaced side lattice trusses and a chord connecting the upper side of said trusses, the inner girder being slidable longitudinally in the space between said trusses of the outer girder, means acting on the bottom of the inner girder for clamping the top of said inner girder against the underside of the chord -of the outer girder, bearing flanges vat one end of the outer girder, said bearingflanges having portions positioned one at each side of the ,end P0111011 of the chord of the outer girder and flush with the upper surface thereof, and other portions'extending laterally beyond the space between said lattice trusses and longitudinally beyond said end of the chord, said outer girder being open at'each end whereby an inner girder may be inserted into each of said open ends, the bottom of the outer girder being open and the inner girder having a'width to permit a it to pass into the opening in the underside of the outer girder, whereby when the clamping means acting on the.

, bottom of the inner girder is released the inner end of the inner girder may drop between the lattice side trusses into an opening in the'bottom ofthe outer girder, and a bearing flange on the end'of the inner girder remote from said end of the outer girder, said latter bearing flange being flush with thetop of the inner girder, being insertable into the outer girder, and extending beyond said end of the inner girder. I

14. A temporary support for concrete construction "as claimed in claim 13in which the upper chord of the outer girder is of inverted U-shape and has outwardlyextending flanges at the lower edges of the legs thereof, .and the respective lattice trusses are secured to said outwardly-extending flanges.

References Cited in'the file of this patent UNITED STATES PATENTS new UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,974,762 March 14, 1961 Emil Mauritz Hunnebeck It is hereby certified'that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 54, for "gridders'" read girders column 4, line 66, for "to" read of column 5, line 67, for "an" read and Signed and sealed this-25th day of July 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Atte ing Offi er Commissioner of Patents 

